Understanding Creep in Materials

Creep is the time-dependent deformation of a material under a sustained load. It is a common phenomenon observed in materials like concrete, plastics, and metals, especially at elevated temperatures for some materials.

Different Types of Creep

Creep in concrete, for instance, can be broadly categorized based on the conditions under which it occurs. The question asks specifically about creep that happens due to loading but without any loss of moisture. Let's look at the options provided:

• Creep: This is the general term for time-dependent deformation under load. It can include deformation due to both loading and moisture change.
• Specific creep: This refers to the creep strain per unit of applied stress. It's a measure of a material's susceptibility to creep under a given stress level.
• Basic creep: This type of creep occurs under sealed or saturated conditions, meaning there is no moisture exchange with the environment. It is solely the deformation caused by the sustained mechanical load.
• Total creep: This represents the sum of basic creep and drying creep (creep that occurs along with drying or moisture loss).

Identifying Creep Without Moisture Loss

Based on the definitions, the type of creep that is specifically due to loading with no loss of moisture (i.e., under constant moisture conditions) is known as basic creep.

When concrete is under load and is allowed to dry, additional creep deformation occurs, known as drying creep or sometimes considered part of total creep alongside basic creep. However, if the concrete is kept in a saturated state or sealed to prevent drying, the creep that still happens is purely due to the load-induced mechanisms within the material structure, and this is precisely what basic creep describes.

Therefore, creep that results from loading while maintaining a constant moisture content (no loss of moisture) is the definition of basic creep.